you need a multimeter that can read amps.....
to do a current draw test
1) remove the negative terminal
2) add the multimeter in SERIES with the neg terminal and negative battery post
3) set the multimeter to AMPS and monitor what the reading is
4) after 5 mins there should be no more than 0.07amps
if it is anymore, go through the fuse box and pull one fuse out at a time, when you see the amps drop to almost zero, the circuit you jst pulled out will be the one that is draining the battery. ie
- 2 amps indicated on multimeter
- remove radio fuse
- amps drops to 0.03 amps
therefore the radio circuit is drawing the current